The present invention relates to controlled motion mechanical members used as a mechanical manipulator and, more particularly, to a motion controllable mechanical manipulator which can be formed from repeated use of components of relatively few component types.
A strong desire for increased automation in the workplace, and a desire to increase the use of animated figures depicting animals, humans or other characters in entertainment situations, use in hazardous environments and other situations, along with an increased ability to control such mechanical manipulators has led to substantial efforts in the development of robotics. As a result, substantial advances have occurred in many aspects of robotics.
Perhaps the most widely used controlled component in robotic systems is a mechanical manipulator, that portion of a robot used to change the position or orientation of selected objects engaged by that manipulator. In many instances, such mechanical manipulators are desired to have capabilities similar to those of the human wrist or shoulder, that is, exhibiting two or more degrees of freedom of motion.
Although a number of such mechanical manipulators have been developed which to a greater or lesser degree achieve some of these desires therefor, many have been relatively complicated devices requiring complicated components and difficult assembly procedures or both. Many, in addition, represent compromises in having relatively limited range, or singularities within the ranges, or other limitations in performance. There has been previously disclosed a mechanical manipulator which can, under control of the user, position objects anywhere over at least a hemispherical surface without any singularities in the operation of the device in this range, and which can be made both reliably and inexpensively.
This manipulator comprises a base support, a pivot holder and a plurality of pivoting links. The pivoting links are rotatably coupled to both the base support and to members of the pivot holder to rotate about axes which extend in different directions for each of these rotatable couplings to a link, typically in accord with specific geometrical arrangements, and in different directions from similar axes in another of such links. These pivot holder members, are in turn in a second coupling, each rotatably coupled to one of a second plurality of pivoting links that are rotatably coupled, in turn, to a manipulable support.
Each of the coupling joints in the manipulator contributes some deflection or deformation when subjected to a sufficiently large mechanical force, or load, being applied thereto. These contributions reduce the mechanical stiffness of the manipulator. Thus, there is a strong desire to reduce the number of coupling joints needed, and to reduce any configurational distortions therein occurring under substantial loads applied thereto.